A 3D Numerical Wave Tank for Coastal Engineering Studies

2017 ◽  
Vol 372 ◽  
pp. 1-10 ◽  
Author(s):  
Eric Didier ◽  
Paulo R.F. Teixeira ◽  
Maria Graça Neves
Keyword(s):  
Wave Tank ◽  
Active Absorption ◽  
Wave Flume ◽  
Long Time ◽  
Mean Water Level ◽  
Wave Maker ◽  
Numerical Beach ◽  
2D And 3D ◽  
3D Applications ◽  
Absorption Wave

This paper presents the validation of active and passive, made by a dissipation beach, numerical absorbing methods implemented in RANS-VOF FLUENT® code for modelling long time series of wave propagation interacting with coastal structures. Verification of both numerical techniques was performed in 2D – wave flume, and 3D – wave tank, this one using a multiple active absorption wave makers. The active absorption wave maker allows maintaining the incident wave generation and the mean water level along the time. Good results were obtained for 2D and 3D applications for active absorption wave maker at the generation boundary and both numerical beach and active absorption at the end of the flume/tank.

A New Control Method of Active Absorption Wave-Maker

2012 ◽  
Vol 591-593 ◽  
pp. 1748-1752
Author(s):  
Hong Wei Li ◽  
Yong Jie Pang ◽  
Guo Cheng Zhang
Keyword(s):  
Control Method ◽  
Wave Generation ◽  
Active Absorption ◽  
Reflected Waves ◽  
Wave Absorption ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Wave Maker ◽  
Active Wave ◽  
Absorption Wave

The theory of 2D wave generation with active wave absorption is outlined. A new control method of active absorption wave-maker is established based on the S plane control (SPC) algorithm in this paper. Using SPC, a piston-type 2D numerical wave flume (NWF) simulation program for simultaneous wave generation and active wave absorption is developed with Boundary Element Method (BEM) and Mixed Eulerian-Lagrangian (MEL). The absorbing wave-making contrast simulation tests for regular wave are also carried out in NWF. Simulation results verify that the controller is robust and well effect for absorbing re-reflected wave is obtained in low reflect condition. Meanwhile, stable wave profile can be output by the absorbing wave-maker in a long time when acute reflected waves appear in the terminal of NWF.

USP Active Absorption Wave Basin: From Conception to Commissioning

2010 ◽  
Author(s):  
Pedro Cardozo de Mello ◽  
Mario Luis Carneiro ◽  
Eduardo Aoun Tannuri ◽  
Kazuo Nishimoto
Keyword(s):  
Digital Filter ◽  
Test Procedure ◽  
Ball Screw ◽  
Frequency Domain Method ◽  
Regular Waves ◽  
Active Absorption ◽  
Wave Flume ◽  
Wave Basin ◽  
The Time Domain ◽  
Absorption Wave

This paper presents the new active absorption wave basin constructed at the University of Sa˜o Paulo (USP), in the Numerical Offshore Tank (TPN) Laboratory. The square (14m × 14m) tank is able to generate and absorb waves from 0.5Hz to 2.0Hz, by means of 148 active flap-type wavemakers. An independent mechanical system drives each flap by means of a 1HP servo-motor and a ball-screw based transmission system. A customized ultrasonic wave probe is installed in each flap, and is responsible for the measurement of wave elevation in the flap. These sensors do not require constant calibration, differently from the capacitive or resistive sensors normally used in similar tanks. A complex automation architecture was implemented, with 3 Programmable Logic Computers (PLC), and a low-level software is responsible for all the interlocks and maintenance functions of the tank. Furthermore, all the control algorithms for the generation and absorption are implemented using higher level software (MATLAB®/Simulink block diagrams). These algorithms calculate the motions of the wavemakers both to generate and absorb the required wave field by taking into account the layout of the flaps and the limits of wave generation. The experimental transfer function that relates the flap motion to the generated wave is used for the calculation of the motion of each flap. Absorption tests were conducted with a prototype wave generator in a 2D wave flume with regular waves. Two different algorithms were tested. The first one is the frequency domain method based on Maeda et al. (2004), in which the commanded variable is the motor velocity. Furthermore, the time domain algorithm proposed by Schaffer (1996) was also tested. It is based on a digital filter and uses the position of the motor as the commanded variable. Both algorithms have hydrodynamic feedback based on the measurement of surface elevation at each flap. The first algorithm needs an extensive test procedure to calibrate its control parameters while the second one, after optimizing the digital filter, is ready to use. Both algorithms presented similar results with reflection coefficient smaller than 10.7% for regular waves in the frequency range of 0.5 to 2.0 Hz. The paper also presents the first results obtained in the tank.

scholarly journals Capsid-like biodegradable poly-glycolic acid nanoparticles for a long-time release of nucleic acid molecules

2021 ◽  
Author(s):  
Clara Guido ◽  
Mariangela Testini ◽  
Stefania D’Amone ◽  
Barbara Cortese ◽  
Maria Grano ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Glycolic Acid ◽  
Cell Transfection ◽  
Biodegradable Poly ◽  
Long Time ◽  
2D And 3D

Capsid-like PGA nanoparticles (NPs) allow sustained cell transfection in 2D and 3D configurations.

Numerical Simulation of Wave Breaking Over a Submerged Step with SPH Method

2018 ◽  
Vol 01 (02) ◽  
pp. 1840005 ◽  
Author(s):  
Hongjie Wen ◽  
Bing Ren ◽  
Guoyu Wang ◽  
Yumeng Zhao
Keyword(s):  
Wave Breaking ◽  
Sph Method ◽  
Vertical Distributions ◽  
Sph Model ◽  
Smoothed Particle ◽  
Mean Water Level ◽  
The Mean ◽  
Wave Maker ◽  
Wave Induced ◽  
Smoothed Particle Hydrodynamic

Wave breaking over a submerged step with a steep front slope and a wide horizontal platform is studied by smoothed particle hydrodynamic (SPH) method. By adding a momentum source term and a velocity attenuation term into the governing equation, a nonreflective wave maker system is introduced in the numerical model. A suitable circuit channel is specifically designed for the present SPH model to avoid the nonphysical rise of the mean water level on the horizontal platform of the submerged step. The predicted free surface elevations and the spatial distributions of wave height and wave setup over the submerged step are validated using the corresponding experimental data. In addition, the vertical distributions of wave-induced current over the submerged step are also investigated at both low and high tides.

scholarly journals On the Assessment of Numerical Wave Makers in CFD Simulations

2019 ◽  
Vol 7 (2) ◽  
pp. 47 ◽  
Author(s):  
Christian Windt ◽  
Josh Davidson ◽  
Pál Schmitt ◽  
John Ringwood
Keyword(s):  
Test Cases ◽  
Cfd Simulations ◽  
Wave Tank ◽  
Free Surface Waves ◽  
Offshore Engineering ◽  
Engineering Problems ◽  
Computational Fluid Dynamics Cfd ◽  
Single Method ◽  
Wave Maker ◽  
Numerical Wave

A fully non-linear numerical wave tank (NWT), based on Computational Fluid Dynamics (CFD), provides a useful tool for the analysis of coastal and offshore engineering problems. To generate and absorb free surface waves within a NWT, a variety of numerical wave maker (NWM) methodologies have been suggested in the literature. Therefore, when setting up a CFD-based NWT, the user is faced with the task of selecting the most appropriate NWM, which should be driven by a rigorous assessment of the available methods. To provide a consistent framework for the quantitative assessment of different NWMs, this paper presents a suite of metrics and methodologies, considering three key performance parameters: accuracy, computational requirements and available features. An illustrative example is presented to exemplify the proposed evaluation metrics, applied to the main NWMs available for the open source CFD software, OpenFOAM. The considered NWMs are found to reproduce waves with an accuracy comparable to real wave makers in physical wave tank experiments. However, the paper shows that significant differences are found between the various NWMs, and no single method performed best in all aspects of the assessment across the different test cases.

scholarly journals Characterization Of Oxide Layers Formed On 13CrMo4-5 Steel Operated For A Long Time At An Elevated Temperature

2015 ◽  
Vol 60 (3) ◽  
pp. 1783-1788 ◽  
Author(s):  
M. Gwoździk
Keyword(s):  
Elevated Temperature ◽  
Oxide Layer ◽  
Steel Substrate ◽  
Scratch Test ◽  
Scanning Microscope ◽  
Oxide Layers ◽  
Optical Scanning ◽  
Long Time ◽  
2D And 3D

Abstract The paper contains results of studies into the formation of oxide layers on 13CrMo4-5 (15HM) steel long-term operated at an elevated temperature. The oxide layer was studied on a surface and a cross-section at the inner and outer surface of the tube wall. The 13CrMo4-5 steel operated at the temperature of 470°C during 190,000 hours was investigated. X-ray structural examinations (XRD) were carried out, microscope observation s using an optical, scanning microscope were performed. The native material chemical composition was analysed by means of emission spark spectroscopy, while that of oxide layers on a scanning microscope (EDS). The studies on the topography of the oxide layers comprised studies on the roughness plane, which were carried out using a AFM microscope designed for 2D and 3D studies on the surface. Mechanical properties of the oxide layer – steel (substrate) were characterised on the basis of scratch test. The adhesion of oxide layers, friction force, friction coefficient, scratching depth were determined as well as the force at which the layer was delaminated.

Sign in / Sign up

Export Citation Format

Share Document